1. Field of the Invention
The present invention relates to a stacking structure of a printed circuit board (PCB) and, particularly, to a stacking structure of a printed circuit board equipped within portable electronic devices.
2. Discussion of the Related Art
During the use of portable electronic devices, such as mobile phones, personal digital assistant (PDAs) and so on, circuit boards, conducting wires and other electronic elements arranged in the portable electronic devices radiate high-band electromagnetic wave. However, such electromagnetic wave not only interferes with the operations of the portable electronic devices, it is also harmful to the human body. In order to reduce the radiation and interference caused by the electromagnetic wave, shielding frames are usually used to shield circuit boards, conducting wires and other electronic elements so as to reduce the negative effect caused by the electromagnetic wave. However, with the development of more and more functions and the miniaturization of the electronic devices, more and more circuit boards are desired to be equipped within an electronic device simultaneously. Therefore, the stacking structure of printed circuit board is applied to satisfy such demand.
Refer to FIG. 6, a typical stacking structure of printed circuit board 10 includes a first printed circuit board 12, a second printed circuit board 14 stacked on the first printed circuit board 12, a first shielding frame 16, a second shielding frame 18, and a plurality of connectors 19. The first printed circuit board 12 includes a first surface 122 and a second surface 124 opposite to the first surface 122. The second printed circuit board 14 includes a first surface 142 and a second surface 144 opposite to the first surface 142. The first surface 122 of the first printed circuit board 12 connects to the first surface 142 of the second printed circuit board 14 via the connectors 19 so as to electrically connect the first printed circuit board 12 to the second printed circuit board 14. A first electronic element 126 is disposed on the second surface 124 of the first printed circuit board 12, and is shielded by the first shielding frame 16. A second electronic element 144 is disposed on the second surface 144 of the second printed circuit board 14, and is shielded by the second shielding frame 18.
As the connectors 19 for connecting the first printed circuit board 12 and the second printed circuit board 14 has a certain thickness, the overall thickness of the stacking structure of printed circuit board 10 is thus increased. Accordingly, such stacking structure of printed circuit board 10 is not suitable to be equipped in portable electronic devices. Meanwhile, the stacking structure of printed circuit board 10 requires two shielding frames for respectively shielding the first printed circuit board 12 and the second printed circuit board 14, and thus the cost of the stacking structure of printed circuit board 10 is relatively high.
Therefore, a new stacking structure of printed circuit board is desired in order to overcome the above-described problems.